The invention relates generally to search radar systems and more particularly to a search radar system with dual scanning rates.
The requirements for effective operation of search radar vary significantly with respect to long-range and short-range targets. In order to detect a long-range target the signal energy radiated in the target direction must be high. This high energy may be achieved by either utilizing a low scanning rate or increasing the rf output power level radiated from the antenna. Since increasing power requires expensive components in the transmitter it is preferable to search for long-range targets with a low scanning rate. This low scanning rate is tolerable for long-range targets since adequate time is available to prepare defenses against the target.
However, for short-range targets, such as sea skimmers and pop-ups, a high scanning rate is required to provide the high date rate needed for defensive preparations. But since the targets are close-in only low signal power is required for accurate detection.
Thus, a search radar effective against both long-range and short-range targets requires a high scanning rate and high average power radiated from the antenna. However, the high power is not required for the detection of short-range targets and the high data rate on long-range targets is of little utility.
Since the extra power required to scan for long-range targets at a high rate increases the cost of the transmitter this waste of power is a significant disadvantage of existing search radar systems.